Epitaxial Growth Chamber Pyrometer Control for Wafer Uniformity
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniform temperature and thickness distribution of epitaxial films across the wafer surface, which is critical for precise processing and uniformity, as non-uniform heating can lead to uneven film formation and manufacturing defects.
Innovation Solution
A system employing multiple frontside and backside pyrometers in combination with a feedback control system to monitor and adjust heating source power and gas flow in real-time, ensuring uniform temperature and thickness distribution by aligning pyrometer measurements across different zones of the epitaxial growth chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple pyrometers and feedback control systems are used to monitor and adjust temperature, then temperature uniformity and film thickness uniformity are improved, but device complexity increases
Solution Approach 1:
The wafer surface is divided into multiple measurement zones, with pyrometers positioned at different locations (center and edge regions) to independently monitor temperature variations. This segmentation allows targeted temperature control for different wafer regions, improving overall film uniformity without requiring excessive measurement points.
Solution Approach 2:
Pyrometers continuously measure thermal radiation from the wafer and film surface, providing real-time temperature data to a feedback control system. The controller adjusts heating element power based on measured temperature deviations, dynamically maintaining temperature uniformity and consequently film thickness uniformity across the wafer surface.
2Manufacturing precision
If real-time temperature monitoring and control is implemented, then film formation uniformity is improved, but processing time and system complexity increase
Solution Approach 1:
Temperature measurements are performed on the wafer backside before epitaxial film growth begins. The feedback control system uses these preliminary measurements to pre-adjust heating element settings, establishing optimal temperature distribution before the time-sensitive film growth process starts, thereby avoiding delays during film formation.
Solution Approach 2:
The pyrometers operate continuously throughout the epitaxial growth process, providing uninterrupted temperature monitoring. This continuous feedback allows real-time adjustments without interrupting the film growth, maintaining process continuity and preventing defects that would arise from stopping and restarting the growth cycle.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables real-time monitoring and control of temperature and thickness uniformity across the wafer, reducing manufacturing defects and ensuring consistent film quality from the center to the edge of the wafer.
Implementation Method 1
Pyrometers are often used to measure temperatures of films and wafer surfaces in a semiconductor processing chamber
Implementation Method 2
measuring temperatures of the film on a front side of the wafer and measuring temperatures on a surface of a backside of the wafer and controlling the applied temperature
Data Source
AI summary
In an embodiment, an apparatus includes a first pyrometer and a second pyrometer configured to monitor thermal radiation from a first point and a second point on a backside of a wafer, respectively, a first heating source in a first region and a second heating source in a second region of an epitaxial growth chamber, respectively, where a first controller adjusts an output of the first heating source and the second heating source based upon the monitored thermal radiation from the first point and the second point, respectively, a third pyrometer and a fourth pyrometer configured to monitor thermal radiation from a third point and a fourth point on a frontside of the wafer, respectively, where a second controller adjusts a flow rate of one or more precursors injected into the epitaxial growth chamber based upon the monitored thermal radiation from the first, second, third, and fourth points.